One particularly versatile type of material handling implement is a so-called loader backhoe, which generally comprises a tractor having a hydraulically-operated front-end loader bucket, and a hydraulically-operated rearwardly-mounted backhoe assembly. This type of equipment can perform a wide variety of different material handling operations, including digging, trenching, and like operations.
In order to promote efficient use of the rearwardly-mounted backhoe, this type of implement typically includes an arrangement whereby the operator can sit in a rearwardly-facing direction for backhoe operation, while sitting forwardly for driving the implement, and for operation of the front-end loader. In many such implements, a dual-position movable seat is provided for the operator, such that the same seat can be positioned in either forwardly-facing or rearwardly-facing dispositions. The controls for the implement are suitably positioned for convenient and efficient operation, depending upon the selected position of the operator's seat.
In view of the multi-purpose nature of a loader backhoe, it is desirable to provide a control system which coordinates operation of the implement's different functions, and facilitates convenient operation by precluding certain functions under certain circumstances. For example, it is sometimes necessary to effect "jump-starting" of this type of implement with suitable electrical jumper cables or the like. During such jump-starting, it is desirable that initiation of engine operation only be effected if the transmission of the implement is in a neutral condition, thus precluding inadvertent movement of the implement upon engine starting. Similarly, it is desirable that engine operation be precluded in the event that the implement's transmission is in gear while the implement is in a condition for backhoe operation. This desirably acts to prevent inadvertent movement of the implement if, during backhoe operation, the stabilizers or outriggers of the backhoe are raised.
In view of the above, it is desirable to provide an interlock control system for a material handling implement which, through the use of suitable sensing arrangements and electrical controls, precludes operation of the implement's engine under certain circumstances.